Soaking of hides



Patented Aug. 2, 1932 UNITED STATES PATENT, OFFICE V THE-RHINE, GERMANY, ASSIGNORS TO. I. G. FARBENINDUSTRIE AKTIEN'GESELL SCHAIT, OI FRANKFORT-ON-THE-MAIN, GERMANY SOAKIN'G 0F RIDES Ho Drawing. Application filed August 8, 1980, Serial 1T0. 474,055, and in Germany August 15, 1989! The present invention relates to the soaking of hides.

It is well known that the soaking of hides and pelts especially those of tropical or subtropical origin which have been dried in the air ofi'ers considerable difiiculty, and is especially difiicult when the hides are large cattle hides which are impregnated with preserving or disinfecting agents containing formalde hyde or mercuric chloride. Hides of this kind can only be soaked and then but incompletely by keeping them for several weeks in pure water and at the same time substantial} losses in the weight of the hides take place.

The accelerating soaking action of alkali metal hydroxides or sulphides, such as caustic soda or sodium sulphide, first occurs with these hides after action for several days, and even then only incompletely, since the hides are immediately converted into a swollen state, which in the normal way should first.

be obtained in the lime pit, without previously becoming soft. The consequence is that the finished leaather shows a coarse and loose grain.

We have now found that a surprisingly rapid and thorough soaking action is obtained by treating the dry hides and pelts with dilute aqueous solutions of water-soluble-amines. such as aliphatic, cycloaliphatic, aromatic orheterocyclic amines which may contain one or more organic radicles with one or more hydroxyl groups. It has been 'found that in this manner a soaking effect is sometimes obtained after 6 hours which could not be obtained with any of the agents hitherto known. At the same time the hides acquire the swelling characteristic of normal soaking whereby they approximate very closely to the soft state of the hide after slaughtering which state is desired to be attained by any softening process. As further advantages may be mentioned, that the soaking agent in no way influences the capacity of the hides for losing the hair in the lime pit (slippiness) and a fine, smooth and compact gram is obtained.

Suitable amines are for example the following amines or mixtures thereof: ethylene diamine, diethylene triamine, ethylene tetramine, propyl amine, dior tri-butyl amine, ethyl hexyl amine, monoor di-cyclohexyl amine, mono-benzyl amine, morpholine or pyridine, piperidine and particularly mono-, dior tri-ethanol amines, monobutanol amine, methyl butanol amine, methyl or dimethyl ethanol amine, cyclohexyl ethanol amine, cyclohexyl butanol amine, methyl ethyl butanol' amine, methyl ethanol propanol ethylene diamine ethanol propanol ethylene tetramine or N- ethanol aniline. The aqueous solutions of the amines may contain from 0.01 to 1 per cent of the amines and usually a content of from 0.05 to 0.3 per cent will give the best results, a content of 0.1 per cent being sufficient in most cases.

The treatment according to the present invention is usually carried out at temperatures below 35 C. and is stopped before the hides or pelts swell considerably i. e. above the degree of swollen state of hides or pelts directly after slaughtering.

The following examples will further illustrate the nature ofthis invention but the in- Dry Java kips which have been disinfecte with a liquid containing formaldehyde are immersed in a soaking liquid which contains 1 gram of mono-ethanol amine per litre of water. The soaking commences after 6 hours. The optimum swelling effect is attained after about 12 hours and the increase in weight (soaking effect) amounts to 210 per cent. Cyclohexyl ethanol amine oen NH- 0 11.011 may be employed instead of the mono-ethanol amine with the same result.

Ewample 2 Dry hides are treated with a solution which contains 1 gram of di-ethanol amine per litre of water. The soaking commences after 24 hours and the optimum swelling amounts to 200 per cent.

Example 3 Dry hides are treated with a solution which contains 1 gram of tri-ethanol amine per litre of water. The soaking commences after 24 hours, the optimum swelling amounts to 200 per cent and the softening to 189 per cent.

Example. 1}

Heavy Rio Grande hides are immersed in a soaking liquid which contains 1 gram of mono-butanol amine per litre of water. After 72 hours the hides are perfectly softened and show a weight of 230 per cent of the dry weight. Instead of the butanol amine ethy ene diamine may be employed.

Ema mp2s 5 Dry Java hips are put into a soak containing 1 gram of methyl butanol amine per each litre of water for 72 hours. After this time 100 kilograms of the dry skins show a weight of 233 kilogram. Instead of the butanol amine propyl amine may be employed.

Eazamgole 6 A soak containing 1 gram of a crude mixture of diand tri-ethanol amine er litre of water augments the weight of ied Java. kips after two days to 213 per cent of their dry weight.

Example '7 A solution of 1 gram of hydroxyethyl aniour hands.

RICHARD KLEIN. HEINRICH ULRICH.

line in 1 liter of water is able to augment the weight of dried goat skins after 48 hours to 268 per cent of their dry weight.

What we claim is:

1. The process for soaking dry hides which comprises immersing the hides in a from 0.05 to 0.3 per cent aqueous solution of an alkylol amine, the treatment being stopped before the hides considerably swell.

2. The process for soaking dry hides which comprlses immersing the hides in a from 0.05 to 0.3 per cent aqueous solution of an ethanol amine, the treatment being stopped before the hides considerably swell.

3. The process for soaking dry hides which comprises immersing the hides in a from 0.01 to per cent aqueous solution of an a lol amine, the treatment being stopped be ore the hides considerably swell.

The process for soaking dry hides which comprises immersing the hides in a from 0.05 to 0.3 per cent aqueous solution of an alkylol amine containing a carbocyclic radicle connected to a nitrogen atom, thetreatment being stopped before the hides considerably swell.

5. The process for soaking dry hides which comprises immersing the hides in a from 0.05 to 0.3 per cent aqueous solution of an aliphatic amine containing at least one ethanol radicle connected to a nitrogen atom, the treatment 

